This invention relates generally to improvements in the arrangement of sensing apparatus for materials such as seed which is distributed from agricultural implements.
The distribution of seed for agricultural purposes is usually accomplished by a tractor pulling a seed dispensing device or several such devices which extend transversely of the tractor's longitudinal axis while the seeds are continuously dispensed in furrows formed in the field. A selective seed planter is disclosed in U.S. Pat. No. 3,387,746 of June 11, 1968 to H. W. Whipple.
For maximum yield, the operator of the tractor controls the number of seeds planted per acre. This is usually accomplished by a counter device which counts the number of seeds dispensed. The counting device may be operated mechanically by the dispensing device or may constitute remote sensors of one type or another. For example, photosensitive elements are disclosed for this purpose in the patent to G. Schenkenberg, U.S. Pat. No. 3,537,091 issued Oct. 27, 1979. Ultrasonic transducer elements are used in the patent to G. G. Fathauser, U.S. Pat. No. 3,881,353, issued May 6, 1975 whereby the detecting apparatus may be operable when the seeds are received through openings of relatively large cross-section. This patent is assigned to the Dickey-John Corporation of Auburn, Ill. Other patents of interest assigned to Dickey-John Corporation include U.S. Pat. Nos. 3,881,631, 3,912,121, 4,149,163 and 4,159,064. An alarm system for blockage in the system is disclosed in U.S. Pat. No. 4,185,224 of Jan. 22, 1980 to S. L. Thompson.
Seed counters such as indicated above may have difficulty maintaining accuracy and may malfunction due to the coincidental receipt of seeds in the sensing area or with dust or moisture collecting on and near the sensors, or because of clogging in or prior to the sensing area.
This invention relates to an agricultural machine, comprising means defining a path along which, in normal operation, a material such as seeds is conveyed.
According to the present invention there is provided a machine comprising means defining a path along which, in normal operation, material is conveyed, there being also provided an indication arrangement having a distance measuring instrument, for monitoring movement of the material along said path, and a display element by which occurrences detected by the distance measuring instrument are rendered sensorily perceptible.
In an advantageous embodiment of the machine, the distance measuring instrument comprises a proximity sensor. The proximity sensor can be mounted in a simple manner at a desired location. In a further embodiment of the machine, the display element comprises a signalling lamp, preferably a light-emitting diode.
The machine may be a device for spreading material.
In a further embodiment, the path defining means comprises a dosing mechanism having a rotatable element by which the material to be spread can be conducted away from a hopper, the distance measuring instrument being arranged near the rotatable element. In this way the operation of the rotatable element forming a dosing member is checked by the indication arrangement so that a satisfactory indication of the correct distribution of the material can be obtained.
For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which: